The present invention relates generally to an improved pressure liquid pumping system, and more specifically to a high pressure liquid pumping system having multiple output pressures and capacities. The system includes a first fluid pump which is normally coupled to the drive motor, along with a second pump which is intermittently coupled to the motor, and is accordingly energized whenever higher output pressures and capacities are desired.
The high pressure liquid pumping system of the present invention is particularly adapted for utilization in the coin operated car wash field. In the period of time that such car wash systems have been utilized, the users have normally responded favorably to those installations having higher pressure or volumes available. While initial modest increases in both pressure and capacity are available from improved water availability and plumbing, these gains were sufficiently small so as to require improved equipment for the pressures and volumes required in today's car wash industry.
As it will be appreciated, increases in pressure and capacity or volume have reached levels which are required only by certain selected customers. Stated another way, the objective of the user will normally determine the pressures and volumes required to accommodate his purpose. Thus, the present system enables the user to select the pressure and volume desired, and upon exercising his selection, he may accomplish the objective with a system having the capabilities to achieve his requirements.
Significant savings in both energy and water volume may be obtained in accordance with the present system. Energy is saved by virtue of a reduction in the overall volume of hot water employed, and further by a reduction in the quantity of soap or detergent which may be utilized to accomplish his objective. Secondly, a reduction in the volume of water passed through the system will be reflected in a reduction in the overall water volume requirements for the system. Hence, a system of the present invention is adapted to match the capability of the equipment by both pressures and volume to the requirements of the user, and accordingly will not overindulge the system with excessive pressures and/or water volumes.
Essentially, the system of the present invention employs a pair of pumps which are normally positive displacement pumps, which operate from a single power source, normally an electric motor. One of the pumps is coupled normally to the motor, and accordingly will be driven at all times. The second pump is intermittently coupled to the motor, such as through an electric clutch or the like, and will be energized in response to a selector switch. Normally, the pumps are supplied by a common supply source, and the outputs from the pumps are coupled together through a single discharge line.
Since positive displacement pumps are being utilized, these pumps are each provided with a pumping chamber having inlet and outlet check valves operatively coupled into the system. In normal operation, therefore, the inlet check valve will resist outward flow from the pumping chamber, and the outlet check valve will resist flow inwardly to the pumping chamber. Thus, the second pump which is only intermittently energized and utilized will neither lose its prime during periods of operation of the first pump alone, nor will the second pump provide a bypass link in the system.